The present invention relates to a semiconductor device manufacturing method.
In a process of manufacturing the semiconductor device, a plasma processing is performed for etching and the like. The plasma processing needs to be performed in a vacuum environment. The plasma processing is therefore performed in a vacuum chamber.
However, even when it is performed in the vacuum chamber, atmospheric air containing nitrogen, oxygen, and the like may sometimes mix into (enter) the vacuum chamber due to an atmospheric air leakage. Such an atmospheric air leakage adversely affects the plasma processing.
As a method of sensing presence of such an atmospheric air leakage, there are known methods described in, for example, Japanese Unexamined Patent Application Publication Nos. Hei 5(1993)-67665 and Hei 7(1995)-50289. In the methods described in Japanese Unexamined Patent Application Publication Nos. Hei 5(1993)-67665 and Hei 7 (1995)-50289, presence of the atmospheric air leakage is sensed by a spectroscope measuring an emission spectrum of nitrogen, oxygen, and the like.